Posted by Hope on .
okay so i feel like a dummie for not knowing this but i need the answer FAST!
Which property would allow you to use mental computation to simplify the problem 27 + 15 + 3 + 5?
1) commutative property of addition
2) distributive property
3) additive identity
4) additive inverse
Please help me

Math 
Reiny,
They clearly want you to mentally group the numbers into
27+3 + 15+5 to quickly in your head find 20+20=40
Now which property lets you do something like
a+b = b+a ?